Anticoagulant drug warfarin, best known as Coumadin, is used to thin the blood and prevent strokes. Currently, it is the best medication there is for preventing ischemic strokes in patients who have an abnormal heart rhythm called atrial fibrillation.
There are other drugs being developed for the purpose, but they have not hit the markets yet.

Besides being effective in preventing ischemic strokes, Warfarin has been linked to another type of stroke called intracerebral brain hemorrhage that results from a ruptured blood vessel and bleeding in the brain.

The rate of such bleedings in the brain has quintupled during the 1990s, especially in people over 80.
The statistics show that the annual rate of intracerebral hemorrhages associated with warfarin was 0.8 cases per 100,000 people back in 1988. In 1999, the rate was 4.4 cases per 100,000 people. In the elderly people over the age of 80, the rate increased from 2.5 in 1988 to 45.9 in 1999.
The prevalence of this side effect is expected to rise in the next couple of years.

Experts advise that doctors need to be cautious with prescribing warfarin. Some patients, especially those at high risk of intracerebral hemorrhages, would be better off without the drug. Doctors need to determine if the benefits outweigh the risks before prescribing Warfarin.

Patients who are using Warfarin, should regularly have blood tests (International Normalized Ratio (INR)) that determines the ability of the blood to clot. If the tests results were high, they would indicate greater risks of bleeding and such patients should avoid Warfarin.

Also, patients who take warfarin need to have regulated blood pressure, since hypertension is likely to increase chances of bleeding.

Health experts said that newer drugs should be introduced for ischemic stroke prevention in order to cut down on the numbers of intracerebral hemorrhages related to warfarin usage.